Packaging

ABSTRACT

The carton and package provide a heat-releasable connection for a closure for a package which is to be heated for use wherein the heat sealed connection will become ineffective when subjected to boiling water conditions. In one form, the closure is a lid for a tray type container. In the second form the closure is a small closure for a small aperture in the lid wherein the size of the aperture is such that it will act as a one-way valve when the package is heated underneath the surface of the water to allow escape of steam or vapor under pressure and to prevent the ingress of water.

United States Patent 1191 Bemiss et al. 4 1 Feb. 13, 1973 54] PACKAGING3,027,261 3/1962 Samara ..,.99/171 H r 3,079,057 2/1963 Colarusso ..22943 x [75] Inventors' P 2,115,340 4/1938 McCrosson... ..229/D1G. 14Alexander Dmald, 9 both 793,107 6/1905 Staunton ..215/56 i 2,235,1013/1941 Enkur ..2l5/56 [73] Assignee: Roblax, Inc., San Francisco, Calif.

22 Filed: June 1,1970

[21] Appl. No.: 41,921

'[561' References Cited UNITED STATES PATENTS 3/1953 Moffett..229/DlG.l4 9/1962 Colman ..229/DIG. 14

Primary ExaminerDonald F. Norton Attorney -Allen and Chromy ABSTRACT Thecarton and package provide a heat-releasable connection for a closurefor a package which is to be heated for use wherein the heat sealedconnection will become ineffective when subjected to boiling waterconditions. In one form, the closure is a lid for a tray type container.1n the second form the closure is a small closure for a small aperturein the lid wherein the size of the aperture is such that it will act asa oneway valve when the package is heated underneath the surface of thewater to allow escape of steam or vapor under pressure and to preventthe ingress of water.

6 Claims, 5 Drawing Figures PATENTEDFEB 13 1973 FIG. l7.

FIG.5

FIG.2

lNVENTOR-S. ROBERT P. BEMISS BY ALEXANDER DONALD ATTORNEYS PACKAGING Thepresent invention relates to packages preferably of the self-openingtype and includes a package such as a tray or carton having flange meansaround its open end, the material of the tray being of a boilablecharacter such as, for example polyethylene, and the lid for the cartonor tray being also of boilable character and comprising paperboard, forexample, coated with a suitable sealant. The present invention alsorelates to methods of cooking food in self-opening type packages underwater by providing for escape of steam or vapor under pressure and forpreventing ingress of water.

It is a general object of the invention to provide an improved carton orpackage for various food products to be sold for example frozen foodproducts whereinv a closure of the package is I loosened or released inresponse to heating as an incident to the heating of the material withinthe tray of the package.

Another object of the invention is to provide a lid which will becomeloosened at temperatures below the boiling temperature of water.

A further object of the invention is to provide an improved carton orlid of the above character wherein the sealant employed which melts toloosen the lid on the carton or tray is placed directly on thepaperboard without any intermediate layer of material so as to beabsorbed at the time of boiling.

Still another object of the invention is to provide a food package forheating by boiling under water in which a small aperture is provided inthe lid for escape of steam or vapor under pressure which aperture isnormally closed by small closure or valve member heat sealed over theopening.

A still further object of the invention is to provide a carton or foodpackage of the above character wherein the size of the apertureissuch'that the small closure over the aperture will act as a one-wayvalve to prevent ingress of water while permitting escape of gases underpressure.

The above and other objects and advantages of the invention will beapparent from the following descriptionof a preferred embodiment thereofas illustrated in the accompanying drawings in which:

FIG. 1 is a perspective view ofa closed package; FIG. 2 is an enlargedfragmentary sectional view taken in a plane indicated by the line 22 inFIG. 1;

FIG. 3 is a fragmentary-perspective view of a modified form of theinvention;

FIG. 4 is a fragmentary sectional view taken in a plane indicated by theline 44 in FIG. 3; and

FIG. 5 is a fragmentary perspective view of a I modified form of theinvention,

Referring to FIGS. 1 and La conventional tray illustrates the type ofpackage which may be employed and this tray l0may be of polyethylene, orother plastic materials, for example,'and of a rigid or semi-rigidconstruction. This tray 10 is provided with a flange 11 extending aroundthe four sides thereof and forming flange meansadapted for connection tothe planar type lid 12 which may be of paperboard, for example, coatedor lined with polyethylene or any suitable sealing material. If desired,the board may be uncoated or it may be selectively coated at differentareas with other sealing composition may be employed which will.

melt at or below 212 F. When the closed tray is placed in a containerwith water part way up the sides of the tray, and subjected to a boilingtreatment to heat the contents of the tray the heat generated willloosen the seal 13 so it becomes ineffective against the gases withinthe package due to the formation of steam and allow escape of thesegases. Also the lid can be readily lifted off from the flange means 11so as to provide access to the package. Usually the heat sealablecompound referred to herein will release at about to 180 F.

The lid may be coated first with polyethylene as a barrier and on this alow melt coating can be applied for release of the lid from the traysuch as the PPDX-l32. Preferably however the sealant such as PPDX-l22 isplaced directly on the paperboard without an intermediate so that as itmelts it will absorb into the board.

Referring to FIGS. '3 and 4, a tray 10 of the character referred to inthe description of FIG. 1 is provided with a lid 120 which also may beof similar construction to the lid 12 of FIG. 1. The lid 12a is providedwith a small aperture 16 at a convenient location and this aperture isnormally closed by a small lid or closure 17 which is secured to the lid12a about the aperture by a ring of the adhesive 18 of the samecharacter as adhesive 13 described with respect to FIG. 2. Preferably,this aperture 16 is of sufficiently small cross section so that theforce of the steam pressure or vapor pressure within the package 10 isinsufficient to break the softened seal around the edge of the cartonbut merely to partially lift the closure 17 so that it acts as a one-wayvalve providing for escape of steam or vapor under pressure from withinthe carton and preventing the ingress of a liquid such as water into thecontents of the carton where the carton is submerged during the heatingstep. In other words, this construction provides a method of heating thecontents of the tray or carton package by submerging it in water and thepackage will effectively remain closed as far as leakage of water to theinside of the package'is concerned. Subsequently, the package can beremoved from the water and the lid 12a lifted off of the tray 11, theheat sealable material 13 being sufficiently heated to allow easierremoval of the lid 12a.

We have found that a diameter of about one-sixteenth to one-eighth inchor less of the aperture 16 will perform satisfactorily in the keepingdown the total force against the tray 12a by relieving the pressureunderneath the lid 12a. At the same time the seal 18 retains sufficientstrength around this aperture 16 to effectively keep the small closure17 in place although loosened to allow escape of steam or vapor underpressure.

Referring to FIG. 5 the lid 12a is provided with special closure 17awhich has a weakened portion in its periphery adjacent to the aperture16, and this weakened portion is formed by a radial cut 19 which extendsfrom the outer edge of the closure 17a inwardly to a point adjacent theopening or aperture 16 but preferably not intersecting this opening.This weakened portion of the closure can be selectively used to controlthe pressure at which the seal provided by the aperture 16 and theclosure 17a will let go or partially let go to allow the escape of gasvapors and/or steam from the interior of the package.

While we have shown and described certain preferred embodiments of theinvention it is apparent that the invention is capable of variation andmodification from the forms shown so that the scope thereof should belimited only by the scope of the claims appended hereto.

We claim:

1. A package comprising a container body having an opening, a lid forthe opening, flange means surrounding the opening, a sealed connectionbetween said lid and the flange means comprising a coating meltable ator below the temperature of boiling water, a small opening in said lid,a closure for said small opening, heat scalable material forming asealing connection between the closure and the lid, both said sealedconnection coating and said heat sealable material forming the sealingconnection being of heat meltable or softening material and said closurefor said small opening forming a one-way valve when subjected tosoftening action so as to permit egress of gas under pressure and toprevent ingress of water.

2. A package comprising a container body having an opening and a lid forthe opening, a small aperture provided in the lid and a closure for saidsmall aperture, said closure having integrally formed means providingfor the escape of gas under pressure from within the package andpreventing ingress of water past said closure, and a sealed connectionseparate and apart from said integrally formed means between said lidand closure in the form of a coating of material heat meltable orsoftening at or below the aperture of boiling water.

3. A package comprising a container body having an opening and a lid forthe opening, a small aperture provided in the lid and a closure for saidsmall aperture, said closure having integrally formed means providingfor the escape of gas under pressure from within the package andpreventing the ingress of water past said closure, and said integrallyformed means comprises a weakened portion.

4. The package as defined in claim 3 including a sealed connectionbetween said lid and closure in the form of a coating of material heatmeltable or softening at or below the temperature of boiling water.

5. A package comprising a container body having an opening and a lid forthe opening, a small aperture provided in the lid and a closure for saidsmall aperture, said closure having integrally formed means providingfor the escape of gas under pressure from within the package andpreventing ingress of water past said closure, said weakened portioncomprises a slit formed in said closure and extending to a pointadjacent to said small aperture.

6. The package as defined in claim 5 including a sealed connectionbetween said lid and closure in the form of a coating of material heatmeltable or softening at or below the temperature of boiling water.

I! i l

1. A package comprising a container body having an opening, a lid forthe opening, flange means surrounding the opening, a sealed connectionbetween said lid and the flange means comprising a coating meltable ator below the temperature of boiling water, a small opening in said lid,a closure for said small opening, heat sealable material forming asealing connection between the closure and the lid, both said sealedconnection coating and said heat sealable material forming the sealingconnection being of heat meltable or softening material and said closurefor said small opening forming a one-way valve when subjected tosoftening action so as to permit egress of gas under pressure and toprevent ingress of water.
 1. A package comprising a container bodyhaving an opening, a lid for the opening, flange means surrounding theopening, a sealed connection between said lid and the flange meanscomprising a coating meltable at or below the temperature of boilingwater, a small opening in said lid, a closure for said small opening,heat sealable material forming a sealing connection between the closureand the lid, both said sealed connection coating and said heat sealablematerial forming the sealing connection being of heat meltable orsoftening material and said closure for said small opening forming aone-way valve when subjected to softening action so as to permit egressof gas under pressure and to prevent ingress of water.
 2. A packagecomprising a container body having an opening and a lid for the opening,a small aperture provided in the lid and a closure for said smallaperture, said closure having integrally formed means providing for theescape of gas under pressure from within the package and preventingingress of water past said closure, and a sealed connection separate andapart from said integrally formed means between said lid and closure inthe form of a coating of material heat meltable or softening at or belowthe aperture of boiling water.
 3. A package comprising a container bodyhaving an opening and a lid for the opening, a small aperture providedin the lid and a closure for said small aperture, said closure havingintegrally formed means providing for the escape of gas under pressurefrom within the package and preventing the ingress of water past saidclosure, and said integrally formed means comprises a weakened portion.4. The package as defined in claim 3 including a sealed connectionbetween said lid and closure in the form of a coating of material heatmeltable or softening at or below the temperature of boiling water.
 5. Apackage comprising a container body having an opening and a lid for theopening, a small aperture provided in the lid and a closure for saidsmall aperture, said closure having integrally formed means providingfor the escape of gas under pressure from within the package andpreventing ingress of water past said closure, said weakened portioncomprises a slit formed in said closure and extending to a pointadjacent to said small aperture.